My computer has 20 GB of memory, but Safari insists on forcibly reloading Slack for using a few hundred megabytes.

Is there a defaults write command, or some other type of tweak, that can disable or at least raise this threshold?

  • Have you considered using the Slack desktop app available both directly from Slack or on the App Store free, it's still the same web app but in a wrapper that definitely doesn't have these issues. Aug 8, 2018 at 18:59
  • Thanks! I was primarily using Slack as an example; this happens on lots of pages and can be pretty annoying. I know I have memory to spare! Aug 8, 2018 at 19:01
  • This isn't an issue I've ever seen with 16GB or RAM, so while this isn't a solution, perhaps the solution isn't bypassing the memory limit, but finding out why you are reaching it so often when my experience of managing numerous student computers on Safari is that I've never seen this message. Aug 8, 2018 at 19:03
  • Do you have any extensions loaded in Safari?
    – jksoegaard
    Aug 8, 2018 at 19:24
  • @jksoegaard Two, neither should be a problem. "Translate" gives me the option to translate pages and shouldn't be running most of the time; Greasemonkey lets me inject user-scripts which could definitely be a culprit, but it's only enabled on two sites. I don't have any adblockers, which probably hurts memory usage, but I want to support the sites I visit! Aug 8, 2018 at 19:40

1 Answer 1


defaults read will tell you what options you can set.

It does not appear that there is a defaults write command available as far as I can tell. It's possible to get a list of the commands with defaults read com.apple.safari and there's quite a few that are cryptic, so I could be wrong though (and would love to be corrected on this as I have this problem too with something that uploads and processes data resulting in losses occurring).

There doesn't seem to be an option in the 'Develop' menu to control this. There is an option to 'Get Safari Technology Preview' that might help if this is changed in an experimental version but that's pure speculation.

Safari 11.2.1 on MacOS 10.13.6 - options will be different on newer/older versions.

  • Generally speaking, I don't think defaults read actually shows every possible value. There are certainly defaults write commands for Finder which I know of that won't show up in a defaults read com.apple.Finder, unless they've been explicitly set or unset previously. Mar 8, 2019 at 0:59
  • That's not all that surprising, but at least these options are considered 'user-serviceable' and relatively safe to modify. Do you know if there's a way to find all the options? I might have to go spelunking into the binaries if I can figure out which files hold the keys but there has to be a better way. I've also heard that MacOS removes plists that 'are not valid' so it might not be possible to set values outside of the set returned by 'defaults read' in future. Validations are getting stricter.
    – antonyh
    Mar 8, 2019 at 10:47

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